Electric household appliances such as dishwashers and refrigerators may be provided with shelves which are adjustable heightwise.
In particular, domestic dishwashers are typically provided with racks intended to receive the dishes to be washed. The racks can usually be extracted in order to make loading and unloading of the dishes easier. Dishwashers may be provided with devices for adjusting the height of the dishwasher racks, this function being useful for optimizing the arrangement of the load. For example, document U.S. Pat. No. 8,567,882 describes a dishwasher rack comprising a height-adjusting mechanism, including a stop cam, which engages the side wall of the rack and allows a movement of the rack upwards with respect to the height-adjusting mechanism. Adjustment of the position of the rack upwards is performed by simply displacing the rack upwards since the cam is kept by gravity in an engaged position with respect to the side wall of the rack. In order to lower the rack the cam must be locked in a disengaged position by raising the rack further. Unlocking of the cam is performed once the rack is fully lowered.
One problem of the solution known from document U.S. Pat. No. 8,567,882 is that the contact surfaces during the cam locking and unlocking operations are subject to wear and possible damage. Moreover, the mode of operation of the device is such that the rack must have a particular form.